Braking action may have had a part in leaving the runway with half the runway remaining because of lack of differential braking to remain straight either by not overriding max braking setting to return to normal brakes or not being able to get adequate braking on the right main gear.
Rudder blanking because of max reverse thrust on the tail mounted engines also could cause the drift left with the 10 knot left crosswind. Reducing reverse should have restored rudder effectiveness. The CVR and FDR info should explain why they didn't regain directional control.